What gm-volt guys think of MNL ...

[shay]

I think you should look at the history of the Volt. First GM claimed that Volt would get 230 MPG

The 230 MPG claim was and is accurate if you understand the machinations which are the CAFE calculations. When calculating CAFE numbers for an electric drive or other vehicle that doesn't use gas, the DOE gives a bonus by assuming that there are roughly 82 kWh in a gallon of gas. The EPA by contrast assumes there are roughly 34 kWh. If you run the numbers the Volt gets over 230 MPG for CAFE purposes: 82/34 X 96 = 231.5 MPG. By comparison the Leaf gets 239 MPG (82/34 X 99). The last number is interesting because Nissan claimed the Leaf would get 367 MPG, which doesn't seem justified. So if you want to criticize GM for the 230 MPG claim you would want to excoriate Nissan for its 367 MPG claim.

Please cite your reference for 230 claim being accurate. I posted this graphic http://wot.motortrend.com/2011-chevrolet-volt-gets-official-epa-rating-9881.html" onclick="window.open(this.href);return false; from another source earlier, but this article shows the official EPA numbers. I do not see 230 MPG on it. As far as 367 claim, I have not seen this claim so I cannot make a comment or criticism.

Edit to add link and official EPA numbers.

 

[davewill]

... The Prius will always use the battery in combination with the gas engine. ...

Not true. It will use only battery if you're easy on the accelerator and driving on surface streets. It tries it's best to stay on battery and when the battery is exhausted, it then changes mode to a more traditional hybrid...as do the others. The fact that it's best is limited is a downside. I maintain that the label PHEV implies this behavior and that Toyota has merely done the worst job of it.

 

[Smidge204]

I think you should look at the history of the Volt. First GM claimed that Volt would get 230 MPG

The 230 MPG claim was and is accurate if you understand the machinations which are the CAFE calculations. When calculating CAFE numbers for an electric drive or other vehicle that doesn't use gas, the DOE gives a bonus by assuming that there are roughly 82 kWh in a gallon of gas. The EPA by contrast assumes there are roughly 34 kWh. If you run the numbers the Volt gets over 230 MPG for CAFE purposes: 82/34 X 96 = 231.5 MPG. By comparison the Leaf gets 239 MPG (82/34 X 99). The last number is interesting because Nissan claimed the Leaf would get 367 MPG, which doesn't seem justified. So if you want to criticize GM for the 230 MPG claim you would want to excoriate Nissan for its 367 MPG claim.

I'd really like a citation on where that calculation procedure is explained, because it doesn't seem to work like you say it works. The 82 kwh/gal number includes a 6.667 multiplier applied to a figure that accounts for upstream energy costs. To just blindly throw that number into a ratio calculation seems stupid, and the fact that you got a number close to 230 strikes me more as a coincidence... especially since, when you use more accurate values (82,049 and 33,705) the result gets less accurate.

The key difference with regards to the claims is that Nissan mentioned the 367 figure only in a tweet (at least I've yet to find it from any other official source), quite possibly poking fun at GM who basically admits the number is virtually meaningless:

"Different methodologies generate different results," Tony Posawatz, vehicle line director for the Chevy Volt, said. "The 230 city mpg is based on the EPA draft methodology. The 130 is based on a DOE calculation. We can quibble over whether to use the EPA or DOE’s methodology, but the bottom line is the Volt’s triple-digit combined city/highway fuel efficiency is game-changing."

So is it 130 or 230, Tony? Any reason you chose the bigger number? Oh yeah, because GM's marketing machine wanted to waste no time parading that number around:

After the EPA number was released, the joke was that banner actually said "23 " instead of "230."

The article I stole that pic from also has a copy of the press release repeating the 230MPG claim.
=Smidge=

 

[stephent]

On the other hand, the scenario I came up with is exactly in line with some Volt supporter's arguments in favor of it: "If my driving habits are such, I'll never even use any gas." Well if your driving habits are such, why are you even buying a car with a gas tank?

I think the argument is "I'll hardly ever use gas", not "I'll never use gas", and we are buying the car with the gas tank for our 10% non-EV miles, because 10% != 0%.

So to evaluate it properly we need case-by-case data. The "gap" into which you are burning more fuel with a Volt than with an BEV+Ice backup is actually quite large.

It depends how many trips you take in the ~40-80 mile range (or double this if you have workplace charging). For daily driving below 40 miles, which it seems most Leaf owners are doing according to Nissan statistics, there's basically no difference. In the "somewhat over Leaf range", the Volt has an advantage in less gas use even if your alternate car has better mileage than the Volt, since you get to cover some of the miles in EV mode rather than none of them. Say you had to go 90 miles (freeway, 65 mph, climate control, rather than trying to eke it out slower in a Leaf), you end up burning 1.8 gallons in a Prius, but only 1.25 in a Volt. And if the Volt's 40 mpg highway is > efficiency than your ICE backup you are saving gas on all the gas miles as well. Plus if you have destination charging available, you get to use EV around your destination, and EV for part of the way back.

For example, every time I go visit my mother, this involves an ~100 mile trip one-way. In the Volt, I end up doing 40 miles EV on the way there, 40 miles EV on the way back, and another maybe 30 miles EV driving around town for a few days while I am there. +120 gas miles, that's about 3 gallons. A Prius would have taken about 4.6. If I had kept my old Civic and bought a Leaf, that would have been 7 gallons. This extra 110 miles of EV driving obliterates the extra 2.5 miles of EV local driving a Leaf would have given me over the Volt so far in my 2.5 months of ownership (from maintenance mode kicking in, plus one time where I exceeded my Volt range by 2 miles).

Take a look at this guy's driving habits. 56% all-electric driving, which means he should be doing ~65miles per day or so. But notice on his graph the sudden jumps?

Since these longer trips exceed a BEV's range he might have rented a car for those times and the gas he burned as a result would be more than offset by the gas he didn't burn during his routine driving.

For this particular driver, I don't think you zoomed in close enough on his graph to get a clear picture of what is going on, since his mileage is so high 100 mile jumps aren't so visible. If you look at the entire range, there are sections that appear kind of flat, but aren't really. If you zoom in close enough to see daily range, you'll see there are days that he doesn't use any gas, and also days where he is doing 100+mile days, more than what would be possible in a Leaf (w/o midpoint charging, which it doesn't appear he routinely has). Not a lot of the 40-80 mile days where a Leaf would be able to "not burn gas during routine driving" while the Volt does. There may well be other drivers in the voltstats data set who are doing 60 miles daily and would be arguably better off in a Leaf, but not this particular driver, from what I see.

But for the most part - and some people don't have enough data yet - it seems a lot of these people could be driving BEVs instead.

If their daily driving is < 40 miles, what difference does it make, why do you care? It's only those with the daily driving in the > volt EV range, < Leaf EV range where the extra range of the pure BEV makes a significant difference in gas consumption.

And yes one could rent an ICE for longer trips. But it's inconvenient to have to deal with pickup & delivery. It's often difficult, more expensive to rent a car with better gas mileage than a Volt. And on a long trip, many would prefer the comfort & familiarity of one's own car, with all your favorite XM stations programmed in, familiar iPod interface, etc.

 

[hodad66]

My most recent stats......

 

[voltcrazy]

The Volt is just a gateway drug to pure EV ownership. :lol:

You have no idea!

I have had my Volt since March of this year. I love driving all-electric, and hate when I have to drive 140 miles and burn gas. I have ICE anxiety, not range anxiety!

I have a deposit on a Tesla Model S, which is pricey. A Leaf is oh-so-close, but not practical for me as a single-car solution *yet* (the Volt is my only car). It would work for me if a DC Fast Charging station is put in between the Bay Area and Manteca, making that 140-mile drive workable.

 

[TomT]

Yawn...

 

[scottf200]

457 miles last week and *used* 0.6 gal of gas.

My favorite EV miles this week were going downtown to see the "Revenge of the electric car"
and charging for "free" at the theater parking garage (just called the 1-888 number on the ChargePoint).

 

[JeffN]

I would call the 230 MPG disingenuous as a minimum and as outwardly fraud like evnow called it. Why would anyone want to buy a car from a company that was recently in bankruptcy and has not been truthful in statements about this particular car?

The Opel Ampera (Chevy Volt with cosmetic changes) gets 196 mpg (1.2L per 100 km) according to the official results published under the mileage testing rules used in Europe (NEDC).

That's not too far from 230 mpg under the U.S. mileage estimate formula that was being considered when GM called their press conference.

The European calculations are described here:

http://opel-ampera.com/wp_en/2011/10/28/combined-and-weighted/" onclick="window.open(this.href);return false;

 

[SanDust]

It tries it's best to stay on battery and when the battery is exhausted, it then changes mode to a more traditional hybrid...as do the others. The fact that it's best is limited is a downside. I maintain that the label PHEV implies this behavior and that Toyota has merely done the worst job of it.

The Prius and the Volt never operate in the same way. For the Prius it's not a question of the battery being exhausted. You can have plenty of battery and the engine will kick on because the traction motor can't provide adequate acceleration. And the reason the traction motor can't provide adequate acceleration is because it has no mechanical advantage. The Volt will never have the engine come on for any purpose so long as the battery hasn't reached its depletion point.

The second difference is what happens when the engine does come on. For the Prius then engine comes on and drives the carrier. IOW the engine directly turns the wheels. In the BYD or the Volt the engine comes on and drives a generator that makes electricity for the traction motor. These are not the same things.

You're just not understanding that the Volt or the BYD is a superset of the Leaf. They have everything that a Leaf has plus they have the means of generating electricity. Generally speaking the order of complexity of the cars would be (1) Volt (2) BYD (3) Leaf. In some ways the Prius or the Fusion are as complex as the Volt but as parallel hybrids they have a completely different architecture.

 

[SanDust]

The key difference with regards to the claims is that Nissan mentioned the 367 figure only in a tweet (at least I've yet to find it from any other official source), quite possibly poking fun at GM who basically admits the number is virtually meaningless:

The 230 MPG number comes from the SAE proposed standards which used a utillization factor. The EPA rejected the proposed standard but that was a mistake, because by evaluating MPG and MPGe separately it has no way of differentiating between an EREV that can go 20 miles on a charge and one that can go 120 miles on a charge. As pointed out, if you look at real world stats the 230 MPG for the city cycle is pretty spot on, and the 230 MPG number is only meaningless because the EPA lacks vision.

My point with the MPGe calculation was to show that 230 MPGe is the number that will be used for the Volt for CAFE purposes. You may think it's a dumb number but it's the number that will count. And Nissan did use the 367 MPG number even if, as you say, it was only in a tweet.

My larger objection is to your using the 230 MPG claim as an indictment of GM. This is rather ridiculous given that Nissan has used, and continues to use, the unsupportable claim that the Leaf has a range of 100 miles. If Nissan can use an outdated drive cycle which represents how people drove in 1964 in Los Angeles as the basis for saying the Leaf has a 100 mile range, what is wrong with GM using an obscure method of calculating MPGe that shows the Volt will get 230 MPGe? As a practical matter, the 230 MPG claim by GM hardly rises to the same level as Nissan't 100 mile range claim, mostly because GM figured out it was a loser while Nissan has simply chosen to double down on its loser, so if you want to indict GM for the 230 MPG claim you need to indict, convict, and sentence Nissan for the 100 mile claim. It's similar to criticizing GM for "killing" the EV-1 while ignoring the war crimes committed by Nissan during WW II. IOW if you live in a glass house it's best not to throw stones.

 

[SanDust]

[I do not see 230 MPG on it. As far as 367 claim, I have not seen this claim so I cannot make a comment or criticism.

I think I was very clear in saying that the calculation was based on the DOE CAFE numbers and not the EPA numbers. You can find the DOE procedure in the federal register or you can use a cheat sheet like this one. http://mit.edu/evt/summary_mpgge.pdf" onclick="window.open(this.href);return false;

As for the EPA numbers, can you show me where on the EPA sticker the Nissan Leaf has a range of 100 miles? I'm only seeing 73 miles. http://www.autoblog.com/2010/11/22/nissan-leaf-snags-99-mpg-rating-on-official-epa-sticker/" onclick="window.open(this.href);return false;

 

[LEAFfan]

457 miles last week and *used* 0.6 gal of gas.
My favorite EV miles this week were going downtown to see the "Revenge of the electric car"
and charging for "free" at the theater parking garage (just called the 1-888 number on the ChargePoint).

400 miles last week and *used* 0 (zero!) gals. of gas.
My favorite BEV miles this week was driving to the DC QC station and getting an 80% charge in less than 30 minutes for free (no calls necessary)! :mrgreen:

 

[JeffN]

The Prius and the Volt never operate in the same way. For the Prius it's not a question of the battery being exhausted. You can have plenty of battery and the engine will kick on because the traction motor can't provide adequate acceleration. And the reason the traction motor can't provide adequate acceleration is because it has no mechanical advantage.

On a Prius, the wheels are driven by the Ring gear and the primary electric motor drives the Ring gear directly. The motor is 60 kW or 80 HP. The real limiting factor is the battery pack since its maximum output is 27 kW and that's due to the overall small size of the pack (compared to a Volt or LEAF). Once the Prius gas engine kicks in it can help mechanically drive the wheels and also generate electricity which helps supplement the battery power going to the larger electric motor.

The second difference is what happens when the engine does come on. For the Prius then engine comes on and drives the carrier. IOW the engine directly turns the wheels. In the BYD or the Volt the engine comes on and drives a generator that makes electricity for the traction motor. These are not the same things.

Since the wheels are driven by the Ring gear in the Prius, the gas engine is mechanically connect to the wheels via the carrier but the wheels won't turn unless the smaller motor connected to the Sun gear gets involved (otherwise the Sun gear would spin rather than the Ring gear). The gas engine in the Prius cannot drive the wheels all by itself.

The Volt is effectively similar when its clutches are configured in serial/parallel hybrid mode. This is a common mode for the Volt after the battery has been drained at highway speeds and even down to 35 mph under light torque requirements.

You're just not understanding that the Volt or the BYD is a superset of the Leaf. They have everything that a Leaf has plus they have the means of generating electricity. Generally speaking the order of complexity of the cars would be (1) Volt (2) BYD (3) Leaf. In some ways the Prius or the Fusion are as complex as the Volt but as parallel hybrids they have a completely different architecture.

The Civic is a parallel hybrid. The Prius and Fusion are serial/parallel or "power split" hybrids and the Volt can play that game as well. The Volt can also act as a serial hybrid as you are describing.

 

[LEAFfan]

The Volt will never have the engine come on for any purpose so long as the battery hasn't reached its depletion point.

That's not what the articles say that I've read. And someone posted on here ( a few days ago or so) that there are at LEAST 3 situations where the ICE will run even if there's juice in the battery pack. Absolutes are rarely true. What you could say to be truthful is that MOST of the time it won't come on.

 

[JeffN]

The Volt will never have the engine come on for any purpose so long as the battery hasn't reached its depletion point.

That's not what the articles say that I've read. And someone posted on here ( a few days ago or so) that there are at LEAST 3 situations where the ICE will run even if there's juice in the battery pack. Absolutes are rarely true. What you could say to be truthful is that MOST of the time it won't come on.

You are probably thinking of my post on Saturday:

http://www.mynissanleaf.com/viewtopic.php?f=10&t=6762&start=70#p149873" onclick="window.open(this.href);return false;

 

[Smidge204]

The Opel Ampera (Chevy Volt with cosmetic changes) gets 196 mpg (1.2L per 100 km) according to the official results published under the mileage testing rules used in Europe (NEDC). That's not too far from 230 mpg under the U.S. mileage estimate formula that was being considered when GM called their press conference.

20% off is "not too far" ? :? How far is too far?

The 230 MPG number comes from the SAE proposed standards which used a utillization factor.

Citations. Citations citations citations. There isn't a single link or document reference in your entire post.

You insist the 230 came from the DOE CAFE method when I provided a quote from a GM representative explicitly stating it's based on an EPA method and not the DOE method. You've yet to actually provide a citation to the DOE method itself, and since you claim to know it you should know where to find it - I spent about 20 minutes searching and failed, so please share your sources.

so if you want to indict GM for the 230 MPG claim you need to indict, convict, and sentence Nissan for the 100 mile claim.

Why? The LEAF can and does get 100+ miles per charge under the conditions similar to what Nissan explicitly states are the conditions to achieve that range. Lots of people have done it. Nissan also explicitly says that under different conditions you get different ranges.

If the Volt is burning gas it will never achieve 230MPG. That number is the product of pure imagination (ratio of CD/CS mode driving). As I argued earlier, only gasoline use that goes to motive power and miles traveled under gasoline burning conditions should be counted - otherwise I can play similar games by having my Jetta towed everywhere (energy source other than the ICE) and claim I get 999MPG+.
=Smidge=

 

[shay]

The key difference with regards to the claims is that Nissan mentioned the 367 figure only in a tweet (at least I've yet to find it from any other official source), quite possibly poking fun at GM who basically admits the number is virtually meaningless:

The 230 MPG number comes from the SAE proposed standards which used a utillization factor. The EPA rejected the proposed standard but that was a mistake, because by evaluating MPG and MPGe separately it has no way of differentiating between an EREV that can go 20 miles on a charge and one that can go 120 miles on a charge. As pointed out, if you look at real world stats the 230 MPG for the city cycle is pretty spot on, and the 230 MPG number is only meaningless because the EPA lacks vision.

My point with the MPGe calculation was to show that 230 MPGe is the number that will be used for the Volt for CAFE purposes. You may think it's a dumb number but it's the number that will count. And Nissan did use the 367 MPG number even if, as you say, it was only in a tweet.

My larger objection is to your using the 230 MPG claim as an indictment of GM. This is rather ridiculous given that Nissan has used, and continues to use, the unsupportable claim that the Leaf has a range of 100 miles. If Nissan can use an outdated drive cycle which represents how people drove in 1964 in Los Angeles as the basis for saying the Leaf has a 100 mile range, what is wrong with GM using an obscure method of calculating MPGe that shows the Volt will get 230 MPGe? As a practical matter, the 230 MPG claim by GM hardly rises to the same level as Nissan't 100 mile range claim, mostly because GM figured out it was a loser while Nissan has simply chosen to double down on its loser, so if you want to indict GM for the 230 MPG claim you need to indict, convict, and sentence Nissan for the 100 mile claim. It's similar to criticizing GM for "killing" the EV-1 while ignoring the war crimes committed by Nissan during WW II. IOW if you live in a glass house it's best not to throw stones.

Please cite your reference to your CAFE claim. By telling me to go look up CAFE standards is not citing. You are putting words into my mouth about the 367 MPG claim. I said I had not heard it not that it was tweated. My statement is 230 MPG is disingenuous so please cite data. By saying go look at real world staticitics then you need to cite these statistics. If they include miles that are driven that are powered by electricity then you are using circular logic.

Are your statements about the EPA's mistake and lack of vision your opinion or is based on a published article?

 

[shay]

[I do not see 230 MPG on it. As far as 367 claim, I have not seen this claim so I cannot make a comment or criticism.

I think I was very clear in saying that the calculation was based on the DOE CAFE numbers and not the EPA numbers. You can find the DOE procedure in the federal register or you can use a cheat sheet like this one. http://mit.edu/evt/summary_mpgge.pdf" onclick="window.open(this.href);return false;

As for the EPA numbers, can you show me where on the EPA sticker the Nissan Leaf has a range of 100 miles? I'm only seeing 73 miles. http://www.autoblog.com/2010/11/22/nissan-leaf-snags-99-mpg-rating-on-official-epa-sticker/" onclick="window.open(this.href);return false;

That link only references MPGe. I am and have been challenging the claim of MPG. Please keep your units straight when responding. You are arguing with me about the 230 MPG by trying to criticize Nissan. Please limit your responses to the 230 MPG claim if you like to open another topic about Nissan's mileage then go ahead.

 

[TomT]

I like this game! Can I play?!

10,000 miles so far this year and used 0 (ZERO) gallons of gas!

400 miles last week and *used* 0 (zero!) gals. of gas.